A gunman who opened fire at a New Jersey mall Monday night later holed up in a back room and shot himself in the head, authorities say.
No one else was injured in the mall shooting.
Richard Shoop's body was found at 3:20 a.m. Tuesday in an obscure part of Westfield Garden State Plaza mall, hours after he fired at least six bullets without striking anyone in the massive shopping center.
He acted alone, authorities say.
"We know that his intent was either suicide or to do something that would cause police to shoot him, which we call 'suicide by cop,'" Bergen County Prosecutor John Molinelli told CNN's "New Day."
"He had more than enough opportunity to be able to shoot other people," including a group adjacent to him, but he didn't, Molinelli said. "Instead, he shot randomly at different locations."
Shots hit the ceiling, an escalator, an elevator and a storefront, the prosecutor said.
The reasons for the shooting remain unclear. Shoop used narcotic drugs and sold drugs as well, Molinelli said.
And he left behind a note referring to the idea that the "end was coming," Molinelli said. "That could mean going to jail, getting arrested, or it could mean suicide." Authorities don't know whether Shoop left the note immediately before going to the mall.
A family member called the authorities after hearing about the shooting, and said they thought Shoop might be the gunman, Molinelli told CNN, but police did not confirm his identity until they found his body.
The melee started around 9:20 p.m. ET Monday night, just as the shopping center was about to close. Thousands of people were still in the mall, Molinelli said.
Shoop, dressed all in black and wearing a motorcycle helmet, walked through the mall armed with a rifle modified to look like an AK-47. The rifle was taken from Shoop's brother, Molinelli said.
Allie Cozic, who works in the mall, said everyone was "running to wherever they could."
"It was almost like when you're watching a horror movie and the killer is walking slowly -- that's what it seemed like," she said. "He was wearing all black -- it almost looked like body armor of some kind. As soon as I saw the gun, I just turned and ran."
Eddie Kahmann, another mall employee, said he heard six or seven gunshots.
"There was just people running like crazy, so I quickly just closed my doors, ran to the back, turned off all the lights, music and everything, just to stay hidden," he said.
The shooting sent panic through the mall and set off a frenzied hunt for the gunman. In the early hours of the search, officials weren't sure whether the shooter was still inside or outside the 2-million-square-foot building.
Signs of trouble
Shoop, 20, was known by local law enforcement. He had a history of drug use and abuse, Molinelli said.
"He at least thought that he was reaching a point where there was no recourse but to take his own life," Molinelli said.
But even as his body lay in a remote room in a construction area, fear still permeated the mall.
More than 100 shoppers were still hiding inside stores early Tuesday morning, unsure of whether they could safely come out. Officers worked to evacuate each store.
-- CNN's Nic Robertson, Susan Candiotti, Eden Pontz and Chuck Johnston contributed to this report.
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